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Nov. 24, 1964 Filed Jul 25, 1962 R. c HEIDNER IGNITION SYSTEM INCLUDINGTHERMQSTATICALLY CONTROLLED MEANS FOR REDUCING POWER OUTPUT 2Sheets-Sheet 1 INVEN TOR.

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GNITION SYSTEM INCLUDING THERMOSTATICALLY CONTROLLED MEANS FOR REDUCINGPOWER OUTPUT Filed July 23, 1962 H I HW 2 Sheets-Sheet 2 United StatesPatent IGNllION SYSTEM INCLUDING THERMOSTATI- CALLY CONTROLLED MEANS FORREDUCING POWER OUTI U'I Richard C. Heidner, lLibertyviiie, Ilh, assignorto Outboard Marine Corporation, Waukegan, ill, a corporation of BelawareFiled July 23, 1962, Ser. No. 211,715 6 Claims. (El. 123-148) Theinvention relates to ignition systems for spark ignition, multi-cylinderinternal combustion engines and has for a principal object the provisionof an ignition system which automatically functions to reduce theoperating power level of the engine when the engine temperature exceedsa predetermined level. Generically, the invention contemplates anignition system incorporating thermostatic means operable incident tooverheating of the engine to interrupt the firing of at least one of thespark plugs while permitting continued sparking operation of at leastanother one of the spark plugs, thereby providing for continuedoperation of the engine at a reduced power level. As a result, if someheat removal can be etfected by the cooling system, the lesser amount ofheat generated by operation at the reduced power level may permitreduction in the operating temperature oi the engine and continuedoperation at such reduced power level at temperatures below saidpredetermined level. In the case of outboard motors, where the cool ingwater drains immediately from the engine block when the engine isstopped, it is often desirable to maintain the engine running at reducedspeed in order to continue coolant flow so as to minimize thepossibility of, freezing of the pistons to the cylinder walls. In anyevent, an immediate reduction in the power level will increase the timeinterval between initial overheating and substantial damage to theengine, thereby affording the operator opportunity to correct anymalfunction or to take such other steps as may be desirable to preventsubstantial damage to the engine.

More panticularly, the invention involves the associ tion of one or morespark plugs with a breaker, together with thermostatically operablemeans for preventing firing of the associated spark plugs when theengine temperature rises above the predetermined level, i.e., becomesoverheated. One or more other spark plugs are arranged to fireindependently of the operation of the thermostatic means. Accordingly,after operation of the thermostatic means, the engine will continue to0p erate, but only at a reduced power output level.

Preferably, the thermostatic means is an electrical switch which isconnected to the primary winding of the ignition coil. If desired, awarning light can also be electrically connected through thethermostatic switch in such manner as to apprise the user to anoverheated engine condition. Other objects of the invention will becomeapparent by reference to the following description and the accompanyingdrawings of four embodiments of the invention.

In the drawings:

FIGURE 1 is a diagrammatic view of a battery-powered ignition circuitincorporating various of the features or" the invention;

FIGURE 2 is a diagrammatic view of a magnetopowered, ignition systemsimilar to that shown in FIG- URE 1;

FIGURE 3 is an enlarged view of the cam means operating the breakersincorporated in the ignition systems shown in FIGURES 1 and 2;

FIGURE 4 is a diagrammatic view of another batterypowered ignitioncircuit incorporating various of the features of the invention;

FIGURE 5 is a diagrammatic view of a magnetopowered ignition systemsimilar to that shown in FIG- URE 4; and

FIGURE 6 is a diagnammatic view of a modified electrical arrangement forpreventing firing of less than all of the spark plugs when the engine isoverheated.

The ignition system 11 shown in FIGURE 1 is specifically designed for afour cylinder, two stroke engine, in which the cylinders are fired insequence at intervals relative to rotation of the crankshaft. Theignition system 11, as is conventional, includes a battery 13 connectedthrough an ignition switch 15 to the primary winding 19 of an igntioncoil 17 which also incorporates a secondary winding 21. The secondarywinding 21 is selectively connectable to four spark plugs (showndiagrammatically at 23, 25, 27 and 29) by a distributor 31 mounted on acrankcraft indicated diagrammatically at 45. Firing of spark plugs iscaused by opening of circuit breakers 33 and 35, two of which areprovided for purposes which will become apparent. As is usual,condensers 49 and 51 are respectively connected in parallel with thebreakers 33 and 35.

The breakers 33 and 35 are operated in the usual way by cam 43 which iscarried on the diagrammatically illustrated cam shaft 45. The cam 43includes opposed lobes 47 arranged for successively engaging theoperating pawls 39 and 41 of the respective breakers 33 and 35 so that,in co-operation with the distributor 31, the spark plugs are tired insuccession. As is also common practice, operation of the distributor 31and opening of the breakers is co-ordinated so that spark plugs 23 and27 are fired incident to opening of the breaker 33, and so that sparkplugs 25- and 29 are fired incident to opening of the breaker 35. Thecylinders associated with spark plugs 23 and 27 should be operablybalanced with respect to each other, so as to produce smooth operationwhen the engine is operating at reduced power, as will be explained.

Reduction of the operating power level, by one half in the embodimentshown in FEGURE 1, is afforded by thermostatically operable means forpreventing firing of the spark plugs 25 and 29 associated with thebreaker 35 when the engine is overheated. Operation of the breaker 33,and firing of the associated spark plugs 23 and 27, are not affected,whereby the engine continues to operate.

The spark plugs 25 and 29 can be prevented from firing by variouselectrical and mechanical means. In FIGURE 1, a thermostaticallycontrolled switch means 37 is employed. The switch means 37 includes anormally closed switch 38a which is connected between, and in serieswith, the primary winding 19 and the breaker 35. When the engine becomesoverheated, the switch 38a opens, and further opening of the breaker 35by the cam 43 does not result in firing of the spark plugs 25 and 29.

Mechanical means can also be employed to prevent firing of the sparkplugs 25 and 29. For instance, when the engine becomes overheated, athermostatically operated mechanical interlock can be provided to retainthe breaker 35 in open position. Thus, there would be no further firingof the spark plugs 25 and 29 while the engine is overheated.

Provision is also included for notifying the operator of the engine ofan overheated engine condition by means of a signal which, in thedisclosed embodiment, takes the form of a warning light 53 wired to abattery 13 through a normally open auxiliary switch 54 incorporated inthe thermostatic switch means 37.

In FIGURE 2 there is illustrated a magneto-powered ignition system 61which functions to produce the same result as the system 11 shown inFIGURE 1, when used in association with a relatively low speed engine,and

which is conventionally modified to accommodate the use of a magneto.Specifically, the primary winding 19 is a part of an ignition coil 17'which is incorporated in a conventional magneto and, at one end, isconnected to the secondary winding 21' and to the breakers 33' and 35 asin FIGURE 1. At its other end, the primary winding is connectablethrough an ignition switch 15 to a ground. The ignition switch 15 alsoserves, when in the on position to connect the warning light 53' to abattery 63 through the auxiliary switch 54 in the thermostatic switchmeans 37.

FIGURES 4 and show, respectively, a batterypowered ignition system 65and a magneto-powered system 67, for a two cylinder, internal combustionengine. The system 65 conventionally includes a battery 69 connectedthrough an ignition switch 71 to a pair of ignition coils 73 and 75,each including primary windings 77 and 79 and secondary windings 81 and83. The secondary windings 81 and 83 are respectively connected to sparkplugs indicated diagrammatically at 85 and 87. Respectively connected toeach of the primary windings 77 and 79 are breakers 89 and 91, whichbreakers are opened by a cam or cams (not shown) driven by thecrankshaft so as to produce a spark at the desired time.

interposed between the breaker 89 and the primary winding 77 is anormally closed, thermostatically controlled switch means 95 whichoperates in the same manner as the switch means 37 shown in FIGURE 1, toopen the circuit between the breaker 89 and the primary winding 77 whenthe temperature of the engine exceeds a predetermined level. As aresult, further firing of the spark plug 85 incident to subsequentopening of the breaker 89 is prevented and continued operation of theengine is at a reduced power level.

The thermostatic switch means 95 also serves, when the engine isoverheated, to connect a warning light 97 to the battery 69.

The magneto system 67,- shown in FIGURE 5, is intended for use with arelatively low speed engine and is identical to the system 65 shown inFIGURE 4, except as conventionally modified to accommodate the use of apair of magnetos incorporating ignition coils 73' and 75. Specifically,one end of each of the primary windings 77' and 79 is grounded. Theother ends of the primary coils 77 and 79', in addition to beingconnected to the respective windings 81' and 83' and the associatedbreakers 89 and 91', are connected to each other through an ignitionswitch 71'.

The ignition switch 71', as in the embodiment shown in FIGURE 2, alsoserves to connect a warning light 97 to a battery 99 through thethermostatic switch means 95' so that when the engine becomesoverheated, the warning light circuit is closed to energize the light97'.

FIGURE 6 shows a modification which is intended es pecially for use withrelatively high speed engines employing magneto ignition circuits, suchas shown in FIG- URES 2 and 5, but which can be employed in any of thedisclosed systems for grounding or shorting the ignition coil. Morespecifically, with the modification shown in FIGURE 6, the thermostaticswitch means 95 includes a normally open switch 96 connecting theprimary winding 7'7 to a ground, thereby efifecting shorting out of theprimary winding 77 and preventing firing of the associated spark plugwhen the engine is overheated. When the modification shown in FIGURE 6is substituted in the circuit shown in FIGURE 2, energizing of theswitch 95 to short out the single coil 17' prevents firing of all thespark plugs.

Although the ignition systems for a four cylinder engine have been shownwith a single ignition coil and a distributor, a four cylinder systemcan be operated without a distributor and with an ignition coil for eachbreaker and associated spark plug in a manner similar to that shown withrespect to the two cylinder embodiments illustrated in FIGURES 4 and 5.Likewise, if desired, the twin cylinder systems can be operated withonly one ignition coil pro vided that a distributor co-ordinated withbreaker operation is also employed. Moreover, the disclosed arrangementscan be adapted for use with multi-cylinder engines having other than twoor four cylinders and are also adaptable for use in four stroke engines,providing the timing is properly correlated.

Accessories, such as a search light or the like, can be connected to thedisclosed ignition circuits at the point indicated by the numeral 101 ineach of FIGURES 1, 2, 4 and 5.

Various of the features of the invention are set forth in the followingclaims.

What is claimed is:

1. In an ignition system for spark ignition, multi= cylinder internalcombustion engines including ignition means for firing of spark plugsassociated with the cylinders, the improvement which comprisesthermostatically controlled means operable incident to heating of theengine above a predetermined level for preventing the firing of at leastone of said spark plugs while permitting continued firing of at leastanother one of the spark plugs.

2. An ignition system in accordance with claim 1 including a warningsignal electrically connectable through said thermostatically controlledmeans to a source of electrical energy and in which saidthermostatically controlled means includes switch means operable,incident to heating of said engine above said predetermined temperaturelevel, to connect said warning signal to the source of electricalenergy.

3. In an ignition system for a spark ignition, multicylinder internalcombustion engine including at least one ignition coil including aprimary winding and a secondary winding, two breakers with one of saidbreakers being connected to the primary winding of said one ignitioncoil, a spark plug associated with each of the cylinders, at least oneand less than all of said spark plugs being connected to the secondarywinding of said one ignition coil and being operably associated withsaid one breaker to produce a spark incident to opening of said onebreaker, and means for opening said breakers to cause the production ofsparks by said spark plugs, the improvement comprising thermostaticallycontrolled switch means connected to the primary winding of said oneignition coil for preventing the firing of said spark plugs connected tothe secondary winding of said one ignition coil and associated with saidone breaker incident to opening of said one breaker when said engine isheated above a predetermined temperature level, and without afiectingthe operation of said spark plugs which are not associated with said onebreaker.

4. An ignition system in accordance with claim 3 wherein saidthermostatically controlled switch means comprises a normally closedswitch connected between, and in series with, said primary winding ofsaid one ignition coil and said one breaker, said switch being openedincident to heating of said engine above a predetermined temperaturelevel.

5. An ignition system in accordance with claim 3 wherein the spark plugsnot associated with said one breaker are connected to the secondarywinding of a second igni tion coil, and said thermostatically controlledswitch means includes a normally open switch connected between saidprimary winding of said one ignition coil and a ground, said switchclosing incident to heating of said engine above said predeterminedtemperature level so as to short out said one breaker.

6. In an ignition system for a spark ignition, multicylinder internalcombustion engine, the combination of an ignition coil having a primarywinding and a secondary winding,

a spark plug associated with one of the cylinders and connected to saidsecondary winding,

a breaker connected to said primary winding, said a 6 breaker beingoperable to cause the production of at least one other spark plugassociated with another a spark at said spark plug, of the cylinders andoperable independently of said thermostatic means operable to preventfiring of said thermostatic means.

spark plug incident to heating of said engine above a predeterminedlevel, and 5 No references cited.

1. IN AN IGNITION SYSTEM FOR SPARK IGNITION, MULTICYLINDER INTERNAL COMBUSTION ENGINES INCLUDING IGNITION MEANS FOR FIRING OF SPARK PLUGS ASSOCIATED WITH THE CYLINDERS, THE IMPROVEMENT WHICH COMPRISES THERMOSTATICALLY CONTROLLED MEANS OPERABLE INCIDENT TO HEATING OF THE ENGINE ABOVE A PREDETERMINED LEVEL FOR PREVENTING THE FIRING OF AT LEAST ONE OF SAID SPARK PLUGS WHILE PERMITTING CONTINUED FIRING OF AT LEAST ANOTHER ONE OF THE SPARK PLUGS. 